Key and key bar



Sept 23, 1958 M. J. coRBET-r, JR 2,852,973

KEY AND KEY BAR Filed June 30, 1953 SPt- 23 1958 M. J. coRBE'r-r, JR2,852,973

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KEY AND KEY BAR Michael l'. Corbett, Jr., North Tonawanda, N. Y.,assignor to rEhe Rudolph Wurlitzer Company, North Tonawanda, N. Y., acorporation of Ollio Application June 30, 1953, Serial No. 365,108

\ Claims. (Cl. 84-423) This invention is concerned generally with anelectronic organ, and more specifically with a key and key bar formounting the same.

This invention is concerned with the provision of a key for anelectronic organ. The key is molded of plastic in a one piececonstruction and is aflixed to a metal member for mounting the key inposition in a keyboard. The plastic key and the metal member or key barto which it is attached have different coeiiicients of thermalexpansion, and care must be taken to avoid bowing or cracking of theparts. The keys must be precisely positioned in the keyboard for a neatappearance and for proper engagement by an organists lingers. The keysmust be mounted only for vertical pivoting motion free from side sway ortwisting which would disturb an organists touch and would hinder properoperation.

It is an object of this invention to provide simplified means formounting a key and key bar in an electronic organ.

Another object of this invention is to provide an improved adjustmentbetween an electronic organ key and key bar and the mechanism actuatedthereby.

Another object of this invention is to provide new or improved means foraiiixing an electronic organ key to a key bar to compensate fordifferent coefficients of thermal expansion of the key and key bar.

More specifically, it is an object of this invention to provide meansfor attaching an electro-nic organ key to a. key bar at spaced` apartpoints in different planes to allow relative movement between the keyand key bar with different thermal changes in dimensions.

Yet another object of this invention is to provide improved means forpositioning an electronic organ key and key bar in a keyboard and forguiding the key and key bar against twisting or lateral movement.

Another object of this invention is to provide electronic organ key andkey bar guiding means having an improved, smooth action.

A further object of this invention is to provide means for mountingelectronic organ keys and key bars so that they are individuallyremovable from the organ without the necessity of ydisassembling anypart of the organ.

Other and further objects and advantages of the present invention willbe apparent from the following description when taken in connection withthe accompanying drawings, wherein- Fig. 1 is a fragmentary perspectiveview of a portion of an electronic organ embodying the principles of theinvention;

Fig. 2 is an end view of the organ on a slightly enlarged scale;

Fig. 3 is a perspective View of an organ key and key bar and the partscooperable therewith on a greatly enlarged scale;

Fig. 4 is a vertical sectional view through the key and key bar as takenalong the line 4-4 of Fig. 3;

Fig. 5 is a vertical sectional view taken along the line 5--5 of Fig. 4;

2,852,973 Patented Sept. 23, 1958 ice Fig. 6 is a perspective View ofthe key taken from below the key;

Fig. 7 is a perspective view of the key bar taken from beneath the keybar;

Fig. 8 is a top view showing the attachment of the key bar to a fixedpart of the organ as taken along the line 8 8 of Fig. 4;

Fig. 9 is a horizontal view partly in section looking up along the line9 9 of Fig. 4;

Fig. 10 is a vertical sectional view similar to Fig. 4 showing amodified key and key bar;

Fig. 11 is a horizontal sectional view along the line 1li-11 of Fig. 10;

Fig. 12 is a perspective view of the key guide device shown in Fig. 10;

Fig. 13 is a vertical view partly in section along the.

line 13-13 of Fig. 12;

Fig. 14 is a vertical sectional view along the line 14-14 of Fig. 12;and

Fig. 15 is a fragmentary sectional view similar to a portion o-f Fig. 10showing the manner in which the key and key bar are removable from theorgan.

Referring now in greater particularity to the figures, wherein similarnumerals are used to identify like parts throughout, an electronic organZtl embodying the principles of the invention is shown in general inFigs. 1 and 2. The organ comprises a cabinet 22 having a pair ofkeyboards 24, a pedal manual 26, and a Volume control pedal 28. A reedbox 30 is suitably supported within the organ cabinet and comprises aplurality of vibratile reed sound generators, and a blower and closedair circuit for vibrating the same. The vibratile reed sound generatorsare of the type disclosed in Hoschke No. 2,015,016 wherein a pickupelement spaced from each reed forms a capacitor therewith. The capacityof each such capaciL tor depends on the spacing between the reed andpickup element, and therefore varies with vibration of the reed. When aD. C. potential is impressed across each reed and associated pickupelement, and A. C. potential is generated which is a function of thevibration of the reed. The electrical oscillations so generated areamplified by suitable electronic amplifying means 32, and the amplitiedoscillations are applied to a loundspeaker 34 for translating theoscillations into audible organ tones.

The physical configuration of the various organ keys in the keyboards 24varies from key to key, but the variations in configuration do not forma part of the subject matter of this invention. Accordingly, only asingle key is illustrated by way of example in Figs. 349, this key beingidentified generally by the numeral 36. The key 36 is of a one piecemolded construction having a iiat upper surface 38 for contact by anorganists inger. The key is provided with longitudinal and transversereinforcing flanges 46 on its under surface and is provided at its rearor inner end with a depressed or downwardly oifset flange or wall 42.The key further is provided near its outer end with a depending skirt orapron 44 having internal shoulders at 46 and having a recess 48 forreceiving a screw head as will be more apparent hereinafter.

A key bar generally designated by the numeral 50 and shown more clearlyin Fig. 7 comprises a channel-shaped body portion 52 having flangesalong its longitudinal edges. The key bar 50 is provided at its outer orfree end with a depending arm 54 having a reversely bent end or tip 56.T he longitudinal flanges of the body portion 52 are terminated short ofthe depending arm 54 as at 58 to impart a certain degree of resilienceto the key bar as will be apparent shortly.

The key 36 is aiiixed to the key bar 5t) at spaced apart points locatedin different planes. Specifically, a screw 61B is countersunk in thedepressed Wall or flange 42 and is threaded into an aperture 62 in thebody 52 of the key bar 50. A second screw 64 extends through the apron44 ofthe key with the head of the screw 48 positioned in the recess 58and with the shank of the screw threaded into an aperture 66 inl thedepending arm/ 54 of the key bar. It will be understood that the screws60 and 64 cany be sheet metal screws fitting into unthreaded aperturesas illustrated in Fig. 4, or they can be machine screws received inthreaded apertures, or they can be machine screws extending throughunthreaded apertures and held in place by nuts. The screw 64 holds thedepending arm S4 against the internal shoulders 46, but does not holdthe arm too snugly against these shoulders at the top of the arm.Therefore, when the key bar 50 is elongated relativey to the key 36 bythermal changes in dimension due to the different expansioncharacteristics of the material of the key and of the. bar,` the upperportionk of the arm 54 merely seats more firmly against the shoulders 46without causing damage to the key or key bar. Similarly, when the keybar contracts relative to the key, the upper portion of the arm 54 pullsaway from the shoulders 46 slightly without causing damage to the key orkey bar. It will be apparent that the junction between the key bar bodyand the depending arm flexes slightly during such relative expansion andcontraction, and it is for this purpose that the longitudinal flanges onthe body of the key bar are terminated short of the junction as at 58.

A leaf spring member 68 is aflixed to the inner end ofthe key bar 50.The leaf spring member 68 includes a flat central portion 70y heldtightly against the top surface of the key bar by fasteners such asrivets 72. One end 74 of the leaf spring member extends outwardly beyondthe end of the key bar and is preset upwardly for proper initialpositioning of the key and key bar as will be apparent hereinafter. Theopposite end 76 of the leaf sprmg member 68 likewise is defiectedupwardly and is provided with an elongated opening 78. A screw 8.0passes through the opening 78 and is threaded into a suitable hole inthe body of the key bar. The clamping surface of the screw head bearsagainst the upwardly deflected spring end 76 which maintains tension andthereby holds the screw 80 in adjusted position.

The outwardly extending end 74 of the` spring member 68 associated witheach key 38 is apertured for receipt of a screw 82 which is threadedinto a horizontal flange 84 of a mounting plate 86 which may extend theentire width of one of the keyboards 24, or which may be formed insections to makev up this length. The horizontal flange 84 is verticallyoffset from the major portion of the plate 86 as may be seen in thedrawings. Preferably the flange 84 is provided with struck out fingers88 extending angularly upwardly on opposite sides of the end 74 of theleaf spring member 68 to prevent pivoting of the key and key bar aboutthe screw 82.

An insulating block 90 is vertically mounted beneath the plate 86 foreach key 38 and carries a plurality of flexible wires 92 forming keyswitch contacts. Insulating rods 94 are positioned beneath the free endsof the wires 92 and carry longitudinally extending conductive inserts96. The rods 94 are under control of organ stop switches so that therods can be rotated to position the conductive inserts 96 for engagementby the wires 92 when it is desired for certain stops to be played. Anactuator 98 in the form of an insulating strip is mounted in verticalposition beneath the plate 86 and is provided with suitable aperturesfor receiving the wires 92. It will be understood that there is anactuator 98 and a set of wires 92 for each key. The actuator 98 isprovided with a reduced neck portion 100 etxending upwardly through asuitable aperture in the plate 86 and carrying a rubber cap or bumper102 positioned for engagement by the screw 80. When the key 3,8 isdepressed, the screw 80`pushes down on the rubber cap 102 to lower theactuator 98 and thereby to deflect the wires 92 into contact with the 4insulating rods 94 or conductive inserts 96 carried thereby to completea circuit to the reeds.

The plate 86 is provided along its front edge with a downturned flange104 to which is affixed by suitable means such as screws or welding avertically upstanding flange 106 of a key control plate 108. This plateis provided with a substantially Z-saped bracket 110 extendingsubstantially from edge to edge of the plate 108. The bracket 110 has anupper, horizontal flange 112 parallel tothe plate 108, and the flange112 and plate 108 are provided with aligned slots 114. These slotsreceive the depending stem or leg 116 of a T-shaped guide member 118.The transverse arms 120 of the guide member are secured within thechannel-shaped body portion 52 of the key bar 50 near the outer endthereof and are secured thereto by means such as welding or rivets 122.Strips 124 of polyethylene plastic are secured along the upper surfacesof the flange 112 and the plate 108 in the vicinity of the apertures 114and are held in place by means such as screws or rivets. rIhepolyethylene strips are provided with apertures 126 forming relativelysnug fits with the stern or shank 116 of the guide 118, the apertures114 being large enough so that the stem or shank 116 does: not contactthe metal of the bracket 110 or the plate 108. The fitting of the stem116 through the spaced apart guide apertures in the polyethylene stripsguides the key 38 for movement without lateral shifting or twisting,while the engagement of the metal of the guide 1178 against thepolyethylene strips provides a smooth action and a vpleasant touch tothe organist.

The extreme outer edge of the plate 108 is turned up to form a rightangle flange 128. A felt strip 130, is secured to the upper surface ofthe plate 108 adjacent the flange 128 and is engageable by the apron 44of the key 36 to limit downward movement of the key. A similarfelt strip132 is secured on the undersurface of. a right angle bracket 134 affixedto the underside of the plate 108. The depending arm 54 of the key bar50 projects through a suitable aperture 136 in the plate 108 with thehorizontally disposed tip 56 underlying the felt strip 132 which limitsupward movement of the key.

The upward inclination of the outer end 74 of the leaf spring memberplaces a slight initial tension on the leaf spring member to maintainthe key in its uppermost position with the tip 56 against the upstop.Downward pressure on the key causes the leaf spring member 68 to flexuntil the apron 44 engages the downstop to prevent further depression ofthe key. -It will be apparent that the guide 118 as well as the upwardlystruck sections 88 prevents pivoting of the key and key har about themounting screw 82.

A modified structure is shown in Figs. 1.0-15. Many of the parts of themodified structure are similar to those previously disclosed, and suchparts will be identified by similar numerals with the addition of thesufiix a. The key 36a is identical with that previously disclosed, beingof one piece molded construction and having an upper surface 38a and adepending skirt or apron 44a with a screw head recess 48a and internal.shoulders 46a. The key bar 50a is in part similar to that previouslydescribed and has a channel-shaped body portion 52a with a depending arm54a. The key 36a is held on the key bar 50a.

by screws 60a and 64a in different planes as previously described. Thekey is pivotally mounted in the same manner previously set forth bymeans of a leaf spring,

member 68a having a central body portion 70a riveted to the key bar asat 72a. The leaf spring member 68a is provided with upwardly deflectedends 74a and 76a for the purposes previously described.

Improvement in the structure of Fig. 10 is found in the guiding meansand the limit stops for limiting up and down movement of the key. A keyguide 138 takes the form of a metal channel 140 lying on its side. Thehorizontal flanges 142 of this channel are maintained in proper spacedapart relation by a plurality of cylindrical spacers 144. Screws 146pass through suitable apertures in the sheet metal channel 140 and arethreaded into the ends of the spacers 144. The guide 138 is providedwith a plurality of vertical slots or guideways 148 extending across theweb 150 of the channel and partway into the flanges 140. The web andadjacent portions of the flanges are coated inside and out with layers152 and 154 of polyethylene plastic with the plastic covering the edgesof the slots 148. As will be understood, the polyethylene plastic may becast directly on the sheet metal channel member, thereby obviating theneed for fasteners to secure the plastic in position as it will be heldby the plastic sections fitting through the slots 148. It further willbe understood that-the plastic could be fo-rmed in one or more sheetswhich would be attached to the metal channel by means such as screws orrivets.

The depending arm 54a of the key bar is provided with a right angle ange152 which is adapted to fit into one of the slots 148 and to formcontact with the polyethylene therein. The flange 152 is formed ofmetal, and the engagement of the metal flange with the polyethylene inthe guide slots 148 provides a smooth action and a pleasant feel to theorganist. Since the flange 152 forms a right angle construction with thedepending arm 54a, a rigid structure is presented. Thus, the sliding ofthe ange 52 within the polyethylene coated slots 154 provides an evenmore positive guiding action preventing lateral deflection or twistingof the key. Further improved positioning is afforded by thisconstruction by virtue of the fact that the flange 152 is locatedimmediately adjacent the screw 64a holding the key on the key bar.

The lower end of the depending arm 46a is provided with a tip 156 whichis rearwardly deeced at right angles to the arm, thus being exactlyopposite to the tip 56. A strip 158 extends the length of the keyboardand is mounted in fixed position. The strip 158 is provided on its uppersurface with a felt layer 160, and on its lower surface with a feltlayer 162. The apron 44a is engageable with the upper felt strip 162 tolimit downward movement of the key, while upward movement of the key islimited =by engagement of the tip 156 with the lower felt strip 162. Itreadily will be seen that only a single member thus is necessary toprovide both an upstop and a downstop, whereas two such members werenecessary in the first construction disclosed.

A further novel feature is found in connection with the structure of thelast discussed modification. By removing the screw holding the upwardlydeflected spring arm 68a, the key and key bar may be pivoted looselyabout the limit stops 158-162 as a fulcrum. Such pivoting movement isillustrated in Fig. 15. It will be seen that the key and key bar thuscan be readily easily removed and replaced without the necessity ofdisassembling any part of the organ.

It will be apparent that the spring mount for the key and key baraffords a positive, yet effective connection ofthe key and key bar tothe stationary part of the organ. The location of the screws holding thekey onto the key bar in spaced apart planes compensates for differencesin thermal expansion. The double guide formed by the spaced slots in thebracket 110 and iby the elongated recesses or slots in the channel 140positively prevents lateral displacement or twisting of the keys, thusat all times presenting a neat appearance and avoiding unwanted motion.The entire structure obviously is simplified, and the engagement of themetal portions of the key bar with the polyethylene plastic provides asmooth action. The upstop and downstop are readily and convenientlyassembled and prevent operation of the key beyond its desired range. Inaddition, the keys are individually removable as just discussed and asshown in Fig. 15.

lt will be understood that the specific examples of the invention shownand described are by way of illustration only and by way of limitation.Structural modifications can be made and form a part of the currentinvention in so far as they fall within the spirit and scope of theappended claims.

The invention is hereby claimed as follows:

1. A key for a musical instrument including a key bar affixed to saidkey, a fixed support, a leaf spring afiixed to said support and to saidkey bar, said spring having an end portion along said key bar extendingat an acute angle therefrom, an adjusting screw extending through saidspring end portion and said bar, and a tone producing actuator incontact with said screw, said screw being locked in adjusted position bysaid spring end portion.

2. A key for a musical instrument as set forth in claim 1 wherein theend of the leaf spring opposite to the end with the adjusting screw isprovided with a single mounting hole, wherein the fixed support isprovided with a corresponding hole, a fastener extending through theholes in the spring end and in the support for mounting the key on lthesupport, and wherein the support is provided with struck up projectionson opposite sides of the hole therein and engageable with the edges ofthe spring to prevent pivoting of the spring about the fastener.

3. A key for a musical instrument as set forth in claim 1 and furtherincluding a depending strip projecting below said key, and guide meanshaving a pair of spaced apart members which are spaced differentdistances from said key, said members having slots therein receivingsaid depending strip for guiding said key and preventing twistingthereof.

4. A key yfor a musical instrument as set for-th in claim 1 wherein thekey bar has a depending member thereon, said key bar and dependingmember having a predetermined coefiicient of expansion, said key havinga different coefficient of expansion and having a depending portionadjacent the depending member on said key bar, means for securing ahorizontal partof said key to a horizontal part of said key bar, andmeans for securing the depending member on said key bar to the dependingportion of said key, the securing means being in different planes toallow slight bending of said key and key bar to compensate for thedifferent coefiicients of expansion.

5. A key for a musical instrument as set forth in claim 4 wherein thedepending key portion has a vertical seat receiving the depending memberon the key bar.

References Cited in the file of this patent UNITED STATES PATENTS1,840,712 Grant Jan. 12, 1932 2,253,782 Hammond et al Aug. 26, 19412,260,412 Stephens Oct. 28, 1941 2,340,050 Gano Jan. 25, 1944 2,495,913Ahern et al Jan. 31, 1950 2,514,978 Terlinde July 11, 1950 2,558,659Mork June 26, 1951 2,567,870 Bozak et a1 Sept. l1, 1951 2,612,812Greenleaf et al. Oct. 7, 1952 2,630,503 Larsen et al. Mar. 3, 1953

